(CBS News) Imagine going to school to pick up your child and not being certain which kid is yours. Imagine brushing your teeth every morning and not wholly recognizing the face in the mirror. All of this is unimaginable for most of us, but a basic fact of life for people with the mysterious neurological condition called "face blindness" -- or prosopagnosia - which can make it almost impossible to recognize faces, even of one's nearest and dearest. Dr. Oliver Sacks knows something about the condition, and not only because he's a neurologist, but also because Dr. Sacks himself is face blind. Lesley Stahl reports.

The following is from the script "Face Blindness" which aired on March 18, 2012. Lesley Stahl is the correspondent. Shari Finkelstein, producer.

Most of us take for granted that we can instantly recognize people we know by looking at their faces. It's so automatic, it almost sounds silly to even say it. Friends can put on a hat, cut their hair, and still we know them by their face. We can do this for thousands upon thousands of faces without ever giving it a moment's thought. But imagine for a second what life would be like if you couldn't, if your wife or husband looked like a stranger; you couldn't tell your kids apart; couldn't recognize yourself in a mirror. Well that's what life is like for people who suffer from a mysterious condition called face blindness, or prosopagnosia, that can make it nearly impossible to recognize or identify faces.

If you've never heard of face blindness, you're not alone -- chances are your doctor hasn't either. It's been unknown to most of the medical world until very recently. Hearing about it can feel a little like entering the twilight zone. But for people who are face blind, the condition is very real.